In modern society, the construction of power transmission and transformation engineering is an important foundation for promoting industrial development and improving the convenience of life, and the transmission line as the key chain of power transmission. This paper breaks down and disassembles the mechanized construction technology of transmission line project in Gobi desert environment from four aspects: apparatus entry, mechanical work, progress coordination and cost control. The improved YOLOv3 detection algorithm is proposed for the real-time detection of the entry and work of the transmission line project equipment in the Gobi desert environment to ensure the safety of the construction site. For the two aspects of schedule coordination and cost control, the constructed schedule-cost-quality balanced optimization model of transmission line project is solved by using the improved ant colony algorithm, and the entropy value-TOPSIS method is used to make decisions on the scheme. The results show that the improved YOLOv3 detection algorithm significantly improves the detection precision of engineering vehicles, and the accuracy rate can reach 88.9% and the recall rate reaches 82.8%; the improved ant colony algorithm is very suitable for multi-objective duration-cost-quality optimization, and the optimal set of solutions obtained can provide a powerful support for decision-making of the managers of transmission line construction projects.